/*  
 * A JavaScript implementation of the RSA Data Security, Inc. MD5 Message  
 * Digest Algorithm, as defined in RFC 1321.  
 * Version 1.1 Copyright (C) Paul Johnston 1999 - 2002.  
 * Code also contributed by Greg Holt  
 * See http://pajhome.org.uk/site/legal.html for details.  
 */

/*  
 * Add integers, wrapping at 2^32. This uses 16-bit operations internally  
 * to work around bugs in some JS interpreters.  
 */
function safe_add(x, y) {
  var lsw = (x & 0xFFFF) + (y & 0xFFFF);
  var msw = (x >> 16) + (y >> 16) + (lsw >> 16);
  return msw << 16 | lsw & 0xFFFF;
}
/*  
 * Bitwise rotate a 32-bit number to the left.  
 */


function rol(num, cnt) {
  return num << cnt | num >>> 32 - cnt;
}
/*  
 * These functions implement the four basic operations the algorithm uses.  
 */


function cmn(q, a, b, x, s, t) {
  return safe_add(rol(safe_add(safe_add(a, q), safe_add(x, t)), s), b);
}

function ff(a, b, c, d, x, s, t) {
  return cmn(b & c | ~b & d, a, b, x, s, t);
}

function gg(a, b, c, d, x, s, t) {
  return cmn(b & d | c & ~d, a, b, x, s, t);
}

function hh(a, b, c, d, x, s, t) {
  return cmn(b ^ c ^ d, a, b, x, s, t);
}

function ii(a, b, c, d, x, s, t) {
  return cmn(c ^ (b | ~d), a, b, x, s, t);
}
/*  
 * Calculate the MD5 of an array of little-endian words, producing an array  
 * of little-endian words.  
 */


function coreMD5(x) {
  var a = 1732584193;
  var b = -271733879;
  var c = -1732584194;
  var d = 271733878;

  for (var i = 0; i < x.length; i += 16) {
    var olda = a;
    var oldb = b;
    var oldc = c;
    var oldd = d;
    a = ff(a, b, c, d, x[i + 0], 7, -680876936);
    d = ff(d, a, b, c, x[i + 1], 12, -389564586);
    c = ff(c, d, a, b, x[i + 2], 17, 606105819);
    b = ff(b, c, d, a, x[i + 3], 22, -1044525330);
    a = ff(a, b, c, d, x[i + 4], 7, -176418897);
    d = ff(d, a, b, c, x[i + 5], 12, 1200080426);
    c = ff(c, d, a, b, x[i + 6], 17, -1473231341);
    b = ff(b, c, d, a, x[i + 7], 22, -45705983);
    a = ff(a, b, c, d, x[i + 8], 7, 1770035416);
    d = ff(d, a, b, c, x[i + 9], 12, -1958414417);
    c = ff(c, d, a, b, x[i + 10], 17, -42063);
    b = ff(b, c, d, a, x[i + 11], 22, -1990404162);
    a = ff(a, b, c, d, x[i + 12], 7, 1804603682);
    d = ff(d, a, b, c, x[i + 13], 12, -40341101);
    c = ff(c, d, a, b, x[i + 14], 17, -1502002290);
    b = ff(b, c, d, a, x[i + 15], 22, 1236535329);
    a = gg(a, b, c, d, x[i + 1], 5, -165796510);
    d = gg(d, a, b, c, x[i + 6], 9, -1069501632);
    c = gg(c, d, a, b, x[i + 11], 14, 643717713);
    b = gg(b, c, d, a, x[i + 0], 20, -373897302);
    a = gg(a, b, c, d, x[i + 5], 5, -701558691);
    d = gg(d, a, b, c, x[i + 10], 9, 38016083);
    c = gg(c, d, a, b, x[i + 15], 14, -660478335);
    b = gg(b, c, d, a, x[i + 4], 20, -405537848);
    a = gg(a, b, c, d, x[i + 9], 5, 568446438);
    d = gg(d, a, b, c, x[i + 14], 9, -1019803690);
    c = gg(c, d, a, b, x[i + 3], 14, -187363961);
    b = gg(b, c, d, a, x[i + 8], 20, 1163531501);
    a = gg(a, b, c, d, x[i + 13], 5, -1444681467);
    d = gg(d, a, b, c, x[i + 2], 9, -51403784);
    c = gg(c, d, a, b, x[i + 7], 14, 1735328473);
    b = gg(b, c, d, a, x[i + 12], 20, -1926607734);
    a = hh(a, b, c, d, x[i + 5], 4, -378558);
    d = hh(d, a, b, c, x[i + 8], 11, -2022574463);
    c = hh(c, d, a, b, x[i + 11], 16, 1839030562);
    b = hh(b, c, d, a, x[i + 14], 23, -35309556);
    a = hh(a, b, c, d, x[i + 1], 4, -1530992060);
    d = hh(d, a, b, c, x[i + 4], 11, 1272893353);
    c = hh(c, d, a, b, x[i + 7], 16, -155497632);
    b = hh(b, c, d, a, x[i + 10], 23, -1094730640);
    a = hh(a, b, c, d, x[i + 13], 4, 681279174);
    d = hh(d, a, b, c, x[i + 0], 11, -358537222);
    c = hh(c, d, a, b, x[i + 3], 16, -722521979);
    b = hh(b, c, d, a, x[i + 6], 23, 76029189);
    a = hh(a, b, c, d, x[i + 9], 4, -640364487);
    d = hh(d, a, b, c, x[i + 12], 11, -421815835);
    c = hh(c, d, a, b, x[i + 15], 16, 530742520);
    b = hh(b, c, d, a, x[i + 2], 23, -995338651);
    a = ii(a, b, c, d, x[i + 0], 6, -198630844);
    d = ii(d, a, b, c, x[i + 7], 10, 1126891415);
    c = ii(c, d, a, b, x[i + 14], 15, -1416354905);
    b = ii(b, c, d, a, x[i + 5], 21, -57434055);
    a = ii(a, b, c, d, x[i + 12], 6, 1700485571);
    d = ii(d, a, b, c, x[i + 3], 10, -1894986606);
    c = ii(c, d, a, b, x[i + 10], 15, -1051523);
    b = ii(b, c, d, a, x[i + 1], 21, -2054922799);
    a = ii(a, b, c, d, x[i + 8], 6, 1873313359);
    d = ii(d, a, b, c, x[i + 15], 10, -30611744);
    c = ii(c, d, a, b, x[i + 6], 15, -1560198380);
    b = ii(b, c, d, a, x[i + 13], 21, 1309151649);
    a = ii(a, b, c, d, x[i + 4], 6, -145523070);
    d = ii(d, a, b, c, x[i + 11], 10, -1120210379);
    c = ii(c, d, a, b, x[i + 2], 15, 718787259);
    b = ii(b, c, d, a, x[i + 9], 21, -343485551);
    a = safe_add(a, olda);
    b = safe_add(b, oldb);
    c = safe_add(c, oldc);
    d = safe_add(d, oldd);
  }

  return [a, b, c, d];
}
/*  
 * Convert an array of little-endian words to a hex string.  
 */


function binl2hex(binarray) {
  var hex_tab = "0123456789abcdef";
  var str = "";

  for (var i = 0; i < binarray.length * 4; i++) {
    str += hex_tab.charAt(binarray[i >> 2] >> i % 4 * 8 + 4 & 0xF) + hex_tab.charAt(binarray[i >> 2] >> i % 4 * 8 & 0xF);
  }

  return str;
}
/*  
 * Convert an array of little-endian words to a base64 encoded string.  
 */


function binl2b64(binarray) {
  var tab = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  var str = "";

  for (var i = 0; i < binarray.length * 32; i += 6) {
    str += tab.charAt(binarray[i >> 5] << i % 32 & 0x3F | binarray[i >> 5 + 1] >> 32 - i % 32 & 0x3F);
  }

  return str;
}
/*  
 * Convert an 8-bit character string to a sequence of 16-word blocks, stored  
 * as an array, and append appropriate padding for MD4/5 calculation.  
 * If any of the characters are >255, the high byte is silently ignored.  
 */


function str2binl(str) {
  var nblk = (str.length + 8 >> 6) + 1; // number of 16-word blocks    

  var blks = new Array(nblk * 16);

  for (var i = 0; i < nblk * 16; i++) blks[i] = 0;

  for (var i = 0; i < str.length; i++) blks[i >> 2] |= (str.charCodeAt(i) & 0xFF) << i % 4 * 8;

  blks[i >> 2] |= 0x80 << i % 4 * 8;
  blks[nblk * 16 - 2] = str.length * 8;
  return blks;
}
/*  
 * Convert a wide-character string to a sequence of 16-word blocks, stored as  
 * an array, and append appropriate padding for MD4/5 calculation.  
 */


function strw2binl(str) {
  var nblk = (str.length + 4 >> 5) + 1; // number of 16-word blocks    

  var blks = new Array(nblk * 16);

  for (var i = 0; i < nblk * 16; i++) blks[i] = 0;

  for (var i = 0; i < str.length; i++) blks[i >> 1] |= str.charCodeAt(i) << i % 2 * 16;

  blks[i >> 1] |= 0x80 << i % 2 * 16;
  blks[nblk * 16 - 2] = str.length * 16;
  return blks;
}
/*  
 * External interface  
 */


function hexMD5(str) {
  return binl2hex(coreMD5(str2binl(str)));
}

function hexMD5w(str) {
  return binl2hex(coreMD5(strw2binl(str)));
}

function b64MD5(str) {
  return binl2b64(coreMD5(str2binl(str)));
}

function b64MD5w(str) {
  return binl2b64(coreMD5(strw2binl(str)));
}
/* Backward compatibility */


function calcMD5(str) {
  return binl2hex(coreMD5(str2binl(str)));
}

module.exports = hexMD5;